<?php

/**
 * Render a mathematical expression as a numeric value
 *
 * Definition terms:
 * - float: If true this field contains a decimal value. If unset this field
 *          will be assumed to be integer.
 *
 * @ingroup views_field_handlers
 */
class views_handler_field_math extends views_handler_field_numeric {

    function option_definition() {
        $options = parent::option_definition();
        $options['expression'] = array('default' => '');

        return $options;
    }

    function options_form(&$form, &$form_state) {
        $form['expression'] = array(
            '#type' => 'textarea',
            '#title' => t('Expression'),
            '#description' => t('Enter mathematical expressions such as 2 + 2 or sqrt(5). You my assign variables and create mathematical functions and evaluate them. Use the ; to separate these. For example: f(x) = x + 2; f(2).'),
            '#default_value' => $this->options['expression'],
        );

        // Create a place for the help
        $form['expression_help'] = array();
        parent::options_form($form, $form_state);

        // Then move the existing help:
        $form['expression_help'] = $form['alter']['help'];
        unset($form['expression_help']['#dependency']);
        unset($form['expression_help']['#process']);
        unset($form['alter']['help']);
    }

    function render($values) {
        ctools_include('math-expr');
        $value = strtr($this->options['expression'], $this->get_render_tokens(array()));
        $expressions = explode(';', $value);
        $math = new ctools_math_expr;
        foreach ($expressions as $expression) {
            if ($expression !== '') {
                $value = $math->evaluate($expression);
            }
        }

        // The rest is directly from views_handler_field_numeric but because it
        // does not allow the value to be passed in, it is copied.
        if (!empty($this->options['set_precision'])) {
            $value = number_format($value, $this->options['precision'], $this->options['decimal'], $this->options['separator']);
        } else {
            $remainder = abs($value) - intval(abs($value));
            $value = $value > 0 ? floor($value) : ceil($value);
            $value = number_format($value, 0, '', $this->options['separator']);
            if ($remainder) {
                // The substr may not be locale safe.
                $value .= $this->options['decimal'] . substr($remainder, 2);
            }
        }

        // Check to see if hiding should happen before adding prefix and suffix.
        if ($this->options['hide_empty'] && empty($value) && ($value !== 0 || $this->options['empty_zero'])) {
            return '';
        }

        return check_plain($this->options['prefix'] . $value . $this->options['suffix']);
    }

    function query() {
        
    }

}
